I’m looking into replacing the mechanical fuel pump with an inline electric fuel pump but I was hoping someone might know what the flow rate should be on a 390. It only has a standard 2 bbl carb on it. Most inline pumps range from 20 to 50 gph but I can’t seem to find any info on the stock mechanical pumps. Any suggestions?

 

The 1976 Ford truck shop manual says that the mechanical fuel pump on the 390 should be able to pump 1 pint in 20 seconds as a minimum; and the static pressure should be 5.0 to 7.0 P.S.I.

 

Why not stay with the stock pump?
Electric needs to be mounted close to the tank the inlet should be wet (below fuel level) as they do not pull fuel well.

Then the wiring. It needs to be run thru a relay so the pump gets full w 12 volts and a oil psi switch so when the motor is not running the pump will not run for safety. Motor catches fire or in a crash where you can not turn the truck off the pump will keep running putting gas on the fire!
Not cool in my book.

Eldebrock carbs like even lower than 5psi so you would need to deal with that too.
Dave - - - -

 

Why introduce hassle? Keep the mechanical pump.

 

Electric fuel pumps with carburetors can be dangerous. A mechanical pump can supply plenty of fuel. NASCAR used mechanical pumps on their engines until they switched to fuel injection.

 

Electric pumps are a cure for a problem that doesn't exist. just keep your mechanical pump.